Sarvenaz Zand

Cartilage Engineering from Ovine Umbilical Cord Blood Mesenchymal Progenitor Cells

We aimed to determine whether three‐dimensional (3D) cartilage could be engineered from umbilical cord blood (CB) cells and compare it with both engineered fetal cartilage and native tissue. Ovine mesenchymal progenitor cells were isolated from CB samples (n = 4) harvested at 80–120 days of gestation by low‐density fractionation, expanded, and seeded onto polyglycolic acid scaffolds. Constructs (n = 28) were maintained in a rotating bioreactor with serum‐free medium supplemented with transforming growth factor‐β1 for 4–12 weeks. Similar constructs seeded with fetal chondrocytes (n = 13) were cultured in parallel for 8 weeks. All specimens were analyzed and compared with native fetal cartilage samples (n = 10). Statistical analysis was by analysis of variance and Students t‐test (p < .01). At 12 weeks, CB constructs exhibited chondrogenic differentiation by both standard and matrix‐specific staining. In the CB constructs, there was a significant time‐dependent increase in extracellular matrix levels of glycosaminoglycans (GAGs) and type‐II collagen (C‐II) but not of elastin (EL). Fetal chondrocyte and CB constructs had similar GAG and C‐II contents, but CB constructs had less EL. Compared with both hyaline and elastic native fetal cartilage, C‐II and EL levels were, respectively, similar and lower in the CB constructs, which had correspondingly lower and similar GAG levels than native hyaline and elastic fetal cartilage. We conclude that CB mesenchymal progenitor cells can be successfully used for the engineering of 3D cartilaginous tissue in vitro, displaying select histological and functional properties of both native and engineered fetal cartilage. Cartilage engineered from CB may prove useful for the treatment of select congenital anomalies.

Heterogeneity of Metastatic Melanoma: Correlation of MITF With Its Transcriptional Targets MLSN1, PEDF, HMB-45, and MART-1.

OBJECTIVES Histologic and molecular heterogeneity is well recognized in malignant melanoma; however, the diversity of expression of new and classic melanoma markers has not been correlated in serial sections of metastases. METHODS We examined and correlated the expression of microphthalmia transcription factor (MITF) with its transcriptional targets, including melastatin (MLSN1/TRPM1), pigment epithelium-derived factor (SERPINF1/PEDF), SILV/PMEL17/GP100 (human melanoma black 45 [HMB-45]), and melanoma antigen recognized by T cells 1 (MART-1)/MLANA, in 13 melanoma metastases in lymph nodes of 13 patients. The expression levels and patterns of marker expression were recorded by a semiquantitative, 4-point ordinal reactivity method. RESULTS Our results showed a consistently robust and diffuse expression of MITF protein in 12 (92%) of 13 metastatic tumors compared with variable expression of MLSN1 (46%) messenger RNA or PEDF (75%), HMB-45 (54%), and MART-1 (46%) proteins. CONCLUSIONS Overall, in melanoma lymph node metastases, MITF protein expression was not tightly correlated with its gene targets. Moreover, the immunoreactivity for MITF, compared with MART-1 and HMB-45, was retained, supporting immunohistochemical detection of MITF as a more sensitive method of detecting metastatic melanoma.